The present invention relates to a heat exchanger, and more particularly to a micro heat exchanger with microchannels formed by a thermally conductive porous network located within heat exchanger channels.
Heat exchangers are used in a wide variety of industrial, commercial, aerospace, and residential settings. The function of many types of heat exchangers is to utilize a multitude of channels to transfer as much heat as possible from one fluid (usually a liquid) to another fluid (usually a gas) in as little space as possible, with as low a pressure drop (pumping loss) as possible.
It is desirable to reduce the size of the heat exchanger needed for a given rate of heat exchange. As the heat exchangers structures shrink in size, i.e., as their surface area-to-volume ratio increases, thermal coupling between the structure and surrounding medium increases. The improved coupling is especially important for heat exchange between solid surfaces and gases, because thermal resistance at the gas-solid interface tends to dominate overall heat transfer. Miniaturization expands the list of available materials that are useful for efficient heat exchange, since small feature size allows effective heat exchange (even for materials with lower thermal conductivity, such as plastics and ceramics). Modification/control of surface chemistry at a local level is also more readily performed using microfabrication techniques.
Various conventional microfabrication techniques have been provided to manufacture a multiple of microchannels in a micro heat exchanger. The microchannels are fabricated in specific materials and designed to have precise levels, size, shape, placement and distribution. Although effective, conventional microfabrication techniques heretofore utilized to fabricate the microchannels are relatively expensive and time consuming which may limit implementation of such micro heat exchangers to relatively expensive thermal control systems.
Accordingly, it is desirable to provide a micro heat exchanger with multitudes of micro flow channels which are conducive to efficient and inexpensive manufacture.